Carburetor



Aug. 21, 1928.

A. W. M CALMONT CARBURETOR Filed April 10 1922 Patented Aug. 21, 1928.

UNITED STATES ALBERTUS 1,681,358 PATENT OFFICE.

w. nccanuon'r, or ron'rrac, MICHIGAN, ASSIGNOIQBY MESNE ASSIGN- MENTS, TO VICTQRE E. NELSON, or roNrIac, MICHIGAN.

CARBURETOB.

Application filed April 10,

The invention relates to carburetors and has for its object the obtaining of higher efficiency when the engine is running at normal or higher speeds and to also obtain satisfactory operation and the requisite power when the engine is running at slow speed under heavy load. 7 i

In the operation of internal combustion engines, it has been found that a predetermined 10 ratio, such as sixteen to one, between the fuel and air will produce the highest efficiency at normal speeds, and a different ratio, such,

for instance, as twelve to one, is desired where theengine is running at slow speed and under heavy. load. As a consequence, a carburetor adjustment which is suitable for low speeds willbe over rich for high speeds. and an adjustment that is proper forhigh speeds will be over lean for low speeds.

It is the object of the present invention to provide a carburetor which will supply a sufficiently rich mixturewhen the engine is running at low speeds under heavy load and which will also cut down on the richness of the mixture at higher speeds so asto secure a greater efliciency. The invention broadly is applicable to diiferenttypes of carburetor, but asspecifically shown and described, it is applied to a particular type.

In the drawings: j

Figure 1 is a vertical central section through the carburetor to which my improvements are applied a Figure 2 is an enlarged View of the meteringi pin;

igure 3 is a front elevation thereof.

A is the carburetor casing having the air passage B extending therethrough, the shutter or air valve O extending obliquely across said passage and hinged at D so as to change its angle as well as to enlarge'the area during its opening movement.- E is the fuel valve which is attached to and is actuatedby the shutter C. This valve is externally of cylindrical form operating in a bearing F and it is provided with a central fuel orifice G for supplying liquid fuel from the interior thereof. Usually with constructions of this type the supply of fuel to the orifice G" is constant and this orifice is therefore in operation at all speeds and for all loads but is supplemented inits action by the second fuel passage. The second passa'ge is formed between the hearing F and a flat surface H on the side of the cylindrical valve terminating or dlIDl-Ilishlllg 1922. Serial No. 550,975.

' with the fuel well. Thus when the valve is lifted by the actuation of the shutter, the passage formed between the bearing and the flat so surfaceon the side of the valve will supply additional fuel to thecarburetor to compen sate for the increased quantity of air passing therethrough. By tapering the fiat surface (that is, making it non-parallel to the axis), the area of the opening may be progressively enlarged in any ratio desired.

With the constructionas thus far described, the fuel valve will rise from to of an inch at slow speeds and full load, and from to of an inch at speeds and loads corresponding to normal operating conditions. If the flat surface H were made deep enough to provide the rich mixture required for. slow speeds and full load, the mixture would be too rich for efliciency under normal operating conditions, since the fiat surface H cannot effectively decrease in depth as it extends downward. The passage formed by the flat surface H is necessarily determined by itsshaL lowest part. q q g In order to provide. the rich mixture at slow speedswithout making the normal op crating mixture too rich for efficiency, I have provided means for cutting down on the area for the discharge of the fuel after the valve has been raised to a predetermined point, the construction being preferably as follows: The orifice G in the valve E is supplied with fuel from a fuel well I through a port J in the wall of the valve and this'portis so located that after the valve has been raised a predetermined distance, it will pass intolthe bearing F and will be cut off from the well. The orifice G is then supplied by a smaller port K, which reduces the discharge and leans the mixture. This will continue until the valve is lowered, whereupon the port J will again be opened and the quantity of fuel discharged by the orifice G will be increased.

Bythis arrangen'ient the rich mixture may be provided while the fuel valve is at the beginning of its travel, as is the case at slow speeds, and leaned down at a point determined by the location of the port J.

It is preferable to extendthe flat surface H by a very shallow passage H entirely to a the top, in order to maintain therein a liquid seal, which causes the fuel valve to act as a pumpunder rapid movement thereof.

As shown, the valve E has a piston L at its lower end, operating in the cylinder which forms the well I. This forms a dash-pot which retards the movement of the fuel valve, thereby correspondingly retarding the movement of the air valve or shutter. The passage within the fuel valve is closed at its lower end so that the only fuel entering such passage is through the ports J and K.

In the operation of the carburetor, when the engine is idling, most of the fuel which is discharged into the air current passes through the orifice G, this being suilicient to keep the engine in operation. As soon, however, as the throttle is opened, the fuel valve E will be raised so that the passage formed by the flat surface H will be opened into the mixing chamber. This will produce a sudden increase in the discharge of fuel, which insures a rich mixture while the engine is still running at low speed. The flat surface I-I preferably has a portion H which is parallel to the axis of the fuel valve and therefore does not either increase or decrease the area of opening. There is also a portion H which is non-parallel to the axis of the fuel valve and which will gradually increase the area of opening as the fuel valve is raised. Therefore, after the passage formed by the flat surface H is first opened, the discharge of fuel therethrongh will be substantially uniform until the port J is sealed by being withdrawn into the bearing F. The amount of fuel from the orifice G is then cut down to thatwhich can enter through the restricted port K, but as the fuel valve E continues to rise, the portions I-I ofthe fiat surface will gradually increase the discharge openl vith the construction as described, the car buretor may be set so as to supply a rich mix ture of fuel when the engine is operating under predetermined speed limits, such, for instance, as 15 miles per hour under light loads or 8 miles per hour under heavy load. At this point the port J will be sealed, which will cut down on the quantity of fuel discharged and will increase the efliciency for speeds greater than 15 miles per hour under light load and 8 miles per hour under heavy load by cutting down on the ratio of fuel. This is advantageous for the reason, above stated, that a richer mixture is required for slow speeds than under normal operating conditions. For still higher speeds the quantity of fuel will be gradually increased by reason of the non-parallel portion H of the flat surface until the highest speed is attained. lVhen the engine is slowed, the reverse effect is produced, the mixture being automatically enriched when the speed drops below 15 miles per hour under light load or 8 miles per hour under heavy load, this continuing until a further under-limit is reached, where the flat surface H will be sealed and the orifice G alone will supply the fuel for the idling of the engine.

The essential feature of my improvement is the automatic leaning of the mixture upon a predetermined increase of motor speed and a corresponding automatic enriching of the mixture upon a predetermined reduction of motor speed, the point of which being so selected as to obtain high efficiency under normal conditions and high power under exceptional conditions.

What I claim as my'invention is:

1. In a carburetor, the combination with an air shutter or valve, of a fuel valve actuated thereby and controlling a plurality of discharge passages for liquid fuel, one of said passages being automatically restricted at a predetermined point in the opening travel of the valve.

2. In a carburetor, the combination with a shutter or air valve, of a fuel valve actuated thereby and controlling a plurality of fuel passages, the metering aperture for one of said passages being progressive] y increased in area during a portion of the upward movement of said fuel valve and that of the other passage being restricted at a predetermined point in the opening movement of the valve.

3. In a carburetor, the combination with a shutter or air valve, of a substantially cylindrical bearing, an upwardly slidable fuel valve controlled by said air valve having a substantially cylindrical portion provided with a flat surface on one side thereof cooperating with said bearing to form a fuel discharge passage as the fuel valve is raised, a fuel discharge orifice having a fuel supply passage within said fuel valve, and means for restricting said supply passage at a prcdetermined point in the lifting of said fuel valve.

4. In a carburetor, the combination with a shutter or air valve, of a fuel valve actuated thereby having a central passage closed at its lower end and provided with a discharge port at its upper end, said fuel valve being of substantially cylindrical form and having a flat surface on the side thereof, there being also a port through the wall of said fuel valve communicating with the fuel passage therein, a bearing through which said fuel valve moves for sealing said port when the fuel valve is lifted beyond a predetermined point, said bearing cooperating with said flat surface to form a fuel passage open when said fuel valve is above a predetermined point, and a fuel wellsurrounding said fuel valve and communicating with said fuel passage between said flat surface and bearing and communicating also with the port to the interior of the fuel valve.

5. In a carburetor, the combination with a shutter or. air valve, of a fuel valve actuated thereby and controlling a plurality of discharge passages for the liquid fuel, one of the said passages passing through the said valve said valve being provided with an inlet port for said last mentioned passage arranged to be open in oneposition of said fuel valve and to be automatically closed upon the further opening of said valve.

6. In a carburetor, the combination with an air shutter or valve, of a fuel valve actuated thereby and controlling a plurality of fuel passages, the metering aperture of one of said passages being progressively increased in area during a portion of the movement of said fuel valve in one direction and that of the other passage being restricted at a predetermined point in the movement of the valve in the same direction.

7. In a carburetor, the combination with a shutter or air valve, of a fuel valve controlled thereby, a bearing in which said fuel valve slides,said fuel valve having a surface spaced from said bearing and cooperating therewith to form a fuel discharge passage, a fuel discharge orifice having a supply passage within said valve, and means for restricting said supply passage at a predetermined point in the opening movement of said fuel valve.

8. In a carburetor, the combination with an air shutter or valve, of a fuel valve actuated thereby, a bearing cooperating with said fuel valve, said fuel valve being provided with a flat surface spaced from said bearing to form a fuel discharge passage, said surface having a portion thereof parallel to the axis of said valve, and a second portion thereof nonparallel to said axis.

9. In a carburetor, the combination With a fuel well of a fuel valve for controlling the passage of fuel from the said well, the said valve controlling a pair of fuel passages, one of the said passages being provided with a plurality of apertures of varying sizes forming communication between the well and the passage, and means for closing the larger of the said apertures to decrease the flow of fuel through the said passage and for increasing the cross-sectional area of the other passage to increase the flow of fuel therethrough upon movement of the valve to a predetermined point.

I In testimony whereof I aflix my signature.

ALBERTUS W. MGCALMONT. 

